Abstract Body (Do not enter title and authors here): Background: Long-term high physical performance athletes are more susceptible to major cardiac adaptations. However, the onset and variations in these adaptations within specific populations, such as Brazilians, remain unclear.
Research Questions: Which significant cardiac adaptations do high-performance athletes (HPA) exhibit compared to non-competitive regular practitioners (NCRP), and if these adaptations are still physiological.
Aims: To evaluate the anatomical adaptations of cardiac chambers resulting from physical exercise in Brazilian HPA.
Methods: This retrospective study analyzed exams conducted from October 2014 to May 2024. We enrolled 28 HPA and 185 NCRP who regularly exercised recreationally. Echocardiograms were performed using a two-dimensional echocardiogram with color Doppler, including atrial measurement by the Teichholz method. Maximum oxygen consumption (VO2max) was assessed by cardiopulmonary exercise testing (CPET).
Results: There was no difference between groups for age (49±15 vs. 53±14 years; p=0.094), body weight (69.3±10.0 vs. 70.0±11.7 kg; p=0.094) and resting heart rate (63±8 vs. 60±13 bpm/min; p=0.684). VO2max (57.6±13.9 vs. 47.3±9.4 ml/kg/min; p<0.001), interventricular septum (9.2±1.2 vs. 9.0±1.2 mm; p=0.094), left atrium (37.6±2.9 vs. 35.1±3.6 mm; p<0.001) and left ventricular end-systolic diameter (34.2±5.1 vs. 31.2±3.3 ml; p<0.001) were higher in HPA, while mass index (91.7±13.9 vs. 83.3±17.6; p=0.051) and left ventricular wall (9.1±1.2 vs. 8.6±1.1 mm; p=0.056) showed a tendency to be higher in HPA compared to NCRP. Left ventricular ejection fraction (LVEF) was lower in HPA in comparison to NCRP (63±6 vs. 66±4; p=0.004). There were correlations between VO2max and diastolic volume (r=-0.17; p=0.031), systolic volume (r=-0.30; p<0.001) and LVEF (r=0.73; p=0.016). In a stepwise backward regression using the median value of 48.7 ml/kg/min for VO2max, right ventricle (OR, 1.208; 95% CI, 1.051-1.389; p=0.07), body mass index (OR, 0.625; 95% CI, 0.466-0.837; p=0.002), and systolic volume (OR, 0.723; 95% CI, 0.542-0.965; p=0.028) were independently associated.
Conclusion: HPA shows echocardiogram-assessed heart changes within clinical range. Increased atrial size and end-diastolic volume, despite proper systole, may affect cardiac filling and function by impairing cardiac output and performance, suggesting early atrial function screening to prevent future diseases in high-performance athletes.